1. Field of the Invention
This invention relates generally to fluid replacing apparatus and is more particularly directed to apparatus for replacing the fluid in automatic transmissions having sealed, or inaccessible hydraulic torque converters and which include a fluid circulating pump and inlet and outlet ports for circulation of the hydraulic transmission fluid to fluid coolers and the like.
2. Description of the Prior Art
The following is a list of prior art encountered in the course of a search of the prior art with which my invention is concerned.
______________________________________ U.S. Pat. No. Title Issued Date Inventor ______________________________________ 1,829,173 A. L. Wirtz COMBINED FLUSHER AND LUBRICANT DISPENSER 1,884,820 Oct. 25, 1932 W. L. Osborne METHOD OF CLEANING LUBRICANT CONTAINERS 3,216,527 Nov. 9, 1965 O. G. Lewis APPARATUS FOR CHANGING CRANKCASE OIL 3,447,636 June 3, 1969 R. J. Bonfilio AUTOMATIC OIL EXCHANGING SYSTEM 3,513,941 May 26, 1970 N. J. Becnel FLUID CHANGE MEANS FOR AUTOMATIC TRANSMISSIONS 4,095,672 Jun. 20, 1978 F. J. Senese APPARATUS FOR REMOVAL OF LUBRICATING COMPOSITION AND METHODS FOR USING SAME 4,331,185 May 25, 1982 J. D. Rinaldo et al. TRANSMISSION FILLER ASSEMBLY 4,745,989 May 24, 1988 J. G. DiMatteo VALVE FOR DRAINING AUTOMATIC TRANSMIS- SION FLUID AND METHOD OF USING SAME ______________________________________
Of the above references, some of which pertain to other activities involving the addition or removal of fluid from various and sundry mechanisms, the Becnel U.S. Pat. No. 3,513,941 for FLUID CHANGE MEANS FOR AUTOMATIC TRANSMISSIONS and the DiMatteo U.S. Pat. No. 4,745,989 for VALVE FOR DRAINING AUTOMATIC TRANSMISSION FLUID AND METHOD OF USING SAME are believed to be the most directly pertinent to my invention. In Becnel and DiMatteo, a method and apparatus are described for draining and refilling the fluid in a motor vehicle automatic transmission. The similarities between Becnel and DiMatteo are almost surprising in that each of them provides a cooler outlet and some arrangement for adding fluid to the transmission either through the filler port or to a return line from the transmission fluid cooler. When a transmission cooler line is opened and drained with no restriction the rate of flow at which the fluid is exhausted rapidly increases and fluid is pumped out of the transmission and torque converter much faster than it can be replaced by being pumped in the return line as specified in Becnel's invention, resulting in a disruption of the usual internal and external fluid flow rates and flow patterns which occur normally; this disruption includes an intermittent, recurrent starvation condition to certain internal transmission components resulting in undue stress and frequent damage to those components. Becnel's invention appears to have the capability to supply fresh fluid into the transmission through the return line from the cooler back to the transmission at a predetermined, pre-selected flow rate, but his invention allowed no clear means of balancing and/or matching that flow rate to the rate at which fluid is normally circulated through the cooler line back to the transmission or regulating the exhausting of aged fluid into the waste receptacle to produce a balanced substitution of fresh fluid for aged fluid.
Exhausting aged fluid through an open, unrestricted transmission cooler line results in a flow rate to and out of that opening which is far in excess of the rate at which fluid is normally circulated through the cooler, because the usual and significant flow resistance provided by the return line to the transmission itself and the internal down-line components has been eliminated by interrupting/opening the transmission cooler line.
DiMatteo's invention specifies an unrestricted exhausting of aged fluid through an open cooler line as Becnel's does and also results in a great increase in rate of flow of fluid through the line leading from the transmission to the cooler line at the point it is exhausted, much greater than normally occurring with a closed cooler line in normal closed-loop circulation. Not only does this result in emptying of the transmission pan and starvation of the internal pump(s) and torque converter as well as other internal components, but Dimatteo's invention does not specify any pumping of fresh fluid in the return line to the transmission thus, completely disrupting internal and external flow rates and flow patterns and resulting in complete lack of lubrication to the bearings and internal parts of the transmission which receive fluid from the line returning from the cooler to the transmission. DiMatteo specifies adding fresh fluid as the aged fluid when drained out of the open, unrestricted transmission cooler line, by manually pouring it through the filler tube with a poorly metered, poorly controlled method not balanced to rate of exhaust flow.
In the course of arriving at the method and apparatus of my invention, the concepts present in Becnel and DiMatteo were utilized in a similar manner and it was discovered that most, if not all, of the transmissions operated upon became excessively hot or were subject to internal damage to the fluid seals, rear bearings, or other internal components because it was impossible to maintain equality between the fluid added and the fluid drained, because it was impossible to maintain normal fluid flow rates and flow patterns external to and internal within the transmission and its component parts. In other words, what is lacking in Becnel or DiMatteo is a realistic, functional, reliable means or a method for maintaining a balance to provide a dynamic equality of fluid added and fluid removed by replacing aged fluid with fresh fluid through an opened transmission cooler line without disrupting normal internal and external flow rates and flow distribution patterns.
It may be noted that in the event fluid is allowed to drain faster than the rate of addition of fluid, the pump or torque converter in a transmission is likely to be starved and then will become excessively hot under which conditions a transmission will self-destruct if permitted to continue in operation. On the other hand, should excessive fluid be added to build up an internal pressure within the transmission, there is a strong likelihood that seals for shafts and/or valves, bearings, or the like or other internal components, within the transmission, may be irreparably damaged with a resulting failure of the transmission under subsequent operating conditions.
The remainder of the patents are understood to be directed to various and sundry arrangements for adding, removing and changing fluid which are believed to be more remotely related to the concepts of my invention as will be explained in more detail below.